[45.04] HETG Observations of Zeta Puppis

We present recent HETG observations of \zeta Puppis (O4f).
These observations are among the first to show
Doppler-broadened X-ray emission lines coming from the
expanding wind. The star \zeta Pup has long been a
touchstone for hot star X-ray studies, dating back to its
use in the successful prediction of early-type stellar wind
X-ray emission and its subsequent confirmation by Einstein.
The much higher resolution attainable using grating
spectroscopy on Chandra (\delta v \approx 500 km/s)
clearly shows resolved emission lines from ions ranging from
helium-like silicon to hydrogen- and helium-like magnesium,
neon, and oxygen. Many of the iron lines which are present
are attributable to Fe XVII. A first attempt at fitting the
line profiles using an 107 K shell of gas expanding at
1000 km/s fits the data reasonably well, a result which can
be compared with the terminal velocity of 2660 km/s. A
multi-temperature, multi-shell model is required for
detailed fitting. As another indicator of the location of
the X-ray emitting regions, we have analyzed the Forbidden,
Intercombination, and Resonance (FIR) line complexes of
helium-like ions, a sensitive density diagnostic. The
derived density is then compared to the range of densities
throughout the wind. We would like to thank NASA for support
of this project under grant NAG5-9226.